Method of preparing an emulsifiable oil



Patented m 17, 1939 T ES PATENT oFFlcE [2,144,260 METHOD or rnn'raigg oAN EMULSIFIABLE William H. Hampton and Norman N. Gay, Berk-- eley,Caliil, assignors to Standard Oil Company. of California, San Francisco,Calif., a corporation of Delaware No Drawing. Application July 15, 1936,Serial No. 90,756

5 tilaims.

This invention relates to a new and improved soluble oil and to aprocess of preparing the same. Although the soluble oil-prepared accord-.ing to the present invention is particularly useful as an insecticideit is also applicable for use as a cutting oil and for other purposes.

The term soluble oil as used herein is intended to designate an 011containing an internal emulsifier which renders the oil readilydispersible in water. Such dispersions of oil in water are, of course,not true solutions. The term soluble oil is nevertheless commonly usedin the trade to designate oils which are readily dispersible oremulsifiable in water with or without vigorous agitation and withoutincorporation of additional emulsifying agents in the water or oil atthe time of emulsification. The term is so used in the presentspecification.

Numerous soluble oils have in the past been prepared, for variouspurposes among which is their use for insect control. Such oils havecontained many different types of emulsifying agents among which havebeen petroleum sulfonates.

In the past when petroleum sulfonates' have been utilized to produceemulsification, it has been found necessary either to use sulfonates inamounts of more than 10% by weight based on the amount of oil or to useauxiliary agents in addition to thesulfonates in order to aid emulsi,fication and to obtain an oil composition readily dispersible in waterto give satisfactory emulsions. Usually as much as 20 to 40% ofsulfonates" by weight based on the amount of the oil has been itemulsiflable. Preparation and isolation of these sulfonates involveexpensive extraction and purification steps. Despitev this fact suchpurification processes have apparently been regarded as necessary andessential to the production of'satisfactory insecticidal soluble oils. v

We have discovered not only that these purification processes are'notnecessary but that they are actually undesirable because heating anddrying in air cause deterioration of the sulfonate compounds. The methodof this invention yields more effective and desirable compounds withless trouble and expense. I v

The present invention enables one to produce a satisfactory soluble oilwithout the addition of such large amounts of petroleum sulfonates aswill render a phytonomic oil distinctlyphytocidal'.

This invention also provides a process which avoids the expensive stepsof separating-the sulfonates from oil, and purifying them by the variouswell known washing treatments. The invention also avoids thedeterioration of the sulfonate compounds incident to heating and dryingthe separated compounds in air.

Accordingly, it is an object of this invention to provide a soluble oilcontaining less than 10% petroleum sulfonates but capable of formingsatisfactory oil in water emulsions.

It is also an object of this invention to provide a process of producingsoluble phytonomic oils utilizing petroleum sulfonates as an internalemulsifier which process omits sulfonate extraction and purificationsteps heretofore regarded as essential or necessary.

A further object of the invention is to provide a phytonomicinsecticidal oil by retaining in the oil reaction products (presumablypetroleum sulfonates) formed in situ by reaction of sulfuric acid on theoil and subsequent neutralization of the reaction products with analkali.

An additional object of the invention is to form a soluble oil by firstextracting a substantial proportion of the sulfonatable hydrocarbonsfroma mineral oil and then'treating the extracted mineral oil withsulfuric 'acid to form reaction products in situ, which, whenneutralized with an alkali and retained in the oil, have the generalcharacteristics of petroleum sulfonates but which are capable ofemulsifying-the oil in water even when. present in proportions of only 2to 10% by weight based on the oil.

Another object of the invention is to provide a method of preparing asoluble oil which avoids deterioration and discoloration of thepetroleum 'sulfonates by exposure of the separated compounds to heat andair.

Attention is directed to the fact that phytenomic oils are relativelyfree from unsaturated; aromatic and other more. reactive or easilysul-afonatable compounds. These types of compounds normally present inmineral oils are the constituents which are generally accepted asresponsible for the phytocidal action of the mineral oils.

these phytocidal constituents and to render the oil phytonomic andsuitable for. application to verdant vegetation as an insecticide.Phytonomic oils made according to the above processes have in general anunsulfonatable residue of approximately 85% or more. 7

Although it is well known that petroleum sulfonates suitable for makingsoluble mineral oils when added in proportions of 20% or more areobtainable from unrefined oils, it does not follow that the samematerials are obtainable from selective solvent extracted oils whichcontain relatively small amounts, if any, of the highly reactive oreasily sulfonatable compounds normally present in a phytocidal oil.Likewise it is believed to be unpredictable that such reaction productsformed in situ in a mineral oil would prove more satisfactory as aninternal emulsifier for insecticidal oils than petroleum sulfonatesobtained from the more reactive mineral oil fraction and by the usualseparation involving alcoholic washes and other purification steps.products are formed by the action of sulfuric acid on mineral oils andit might well be expected that sufficient of such undesirable reactionproducts would be retained in the oil'to reduce or interfere with theemulsifying action of the sulfonate compounds. Also it might be expectedthat undesirable constituents would be retained in the oil in quantitiessufficient to render it phytocidal. Whether the above suggestions orother reasons are responsible for the practice in the art cannot bedefinitely stated, but in any event commercial producers in general haveregarded extraction and purification of petroleum sulfonates asessential to the production of satisfactory insecticidal oils usingthese compounds as emulsifiers.

We have discovered that a mineral oil may be treated to produce reactionproducts in situ which are highly efiicient in amounts as low as 2% inproducing emulsification of the oil. This treatment comprises broadly,reaction I of a solvent extracted mineral oil with sulfuric acid andneutralization of the reaction products while in solution in the oilwith an alkali such as potassium hydroxide, potassium carbonate andsimilar alkaline materials. The neutralized reaction products useful forour purposes are soluble in the oil and retained therein. The potassiumsalts of the sulfuric acid reaction products are more efficient thansodium salts in producing emulsification of the oil. However, the use ofsodium hydroxide and its equivalents as a neutralizing agent is to beregarded as falling within the broader scope of the invention.

By analogy to the reaction of sulfuric acid with unrefined petroleumoils to form sulfonic acids, it is believed that the reaction productsformed by our process may likewise be termed sulfonic acids,

and after neutralization may be designated petroleum sulfonates. Itshould be understood, however, that the scope of the invention orvalidity of the claims is not to depend on a scientifically correctchemical designation of the compounds formed. The phrases petroleumsulfonates, sulfonic acids or reaction products having thecharacteristics of sulfonic acids are, used merely as the mostconvenient and descriptive designation for the reaction products of thepresent invention.

In carrying out the process of our invention it is preferred to treat anoil having aviscosity of from 'to 100 seconds Saybolt at 100 F. Thehydrocarbons of such a suitable oil have an average molecular weight inthe range 'of 200 to 400. This preferred oil yields reaction productsmore efficient in producing emulsification than do heavier or lightermineral oil fractions. This Polymerization able residue of approximately"slble, however, to extract the oil with selective Particular fractionof oil is also the most desirable for use as an insecticide.

It is also preferred to treat these oils so that more than 2% and lessthan 4% of potassium or sodium sulfonates are retained therein as aninternal emulsifier. Although such a procedure is preferred, we are notprecluded from retaining in the oil smaller amounts such as 0.4 to 2%sulfonates and enhancing the emulsifying power of these smallerquantitiesby known means such as surface tension modifiers of the typeof acetone and other low molecular weight ketones, alcohols,

aldehydes, esters, amines, ethers and amides which are soluble in bothoil and water. We make no claim to the addition of these materials perse as our invention but regard their combination with the novel featuresherein'disclosed' as within the broad scope of this invention.

Also we are not precluded from using an emulsifiable oil containing asmuch as 10% of petroleum sulfonates produced according to thisinvention. Where the spray oil is to be applied to plants during thewinter months as a dormant spray as much as 10% petroleum sulfonates maybe utilized without harm to the vegetation. Likewise certain plants aremore resistant to these materials and sufler no ill effects from amountsof sulfonates somewhat greater than 4%.

It is also feasible to produce a spray oil composition according to ourinvention containing as much as 10% petroleum sulfonates and todilutethis product with sufiicient phytonomic oil substantially free fromsulfonates or other emulsifying agents and thereby reduce the proportionof sulfonates to, for example, 2 /2% based on the weight of the oil.Such an alternative obviously is advantageous in converting a dormantspray into one suitable for use during the summer months or forapplication to more sensitive plants. I

To illustrate the process and product of the invention the followingspecific example is given:

A California distillate is first extracted with any known suitableselective solvent, liquid sulfur dioxide for example, to remove the morehighly reactive and easily sulfonatable compounds. Such Californiadistillates usually have an unsulfonatable residue of from 50 to 60%prior to the extraction. In practicing the present invention thedistillate is preferably extracted to give a partially refined rafflnatehaving an unsulfonat- It is possolvents to produce a phytonomic oil ormore unsulfonatable residue) and by more drastic sulfuric acid treatmentproduce sufiicient quantities of sulfonic acids for the purposes of thepresent invention. The sulfur dioxide treated distillate used in thisparticular example had a viscosity of 92 to 97 at 100 F. and anunsulfonatable residue of 80-82%. Nine gallons of this treateddistillate is placed in a lead lined agitator at a temperature not toexceed F. Four and one-half pounds of 15 fuming sulfuric acid are addedwith constant air agitation and agitation is continued for 15 minutesafter all the acid is in. Ninety eight percent sulfuric acid could beused, but a greater amount than that represented bythe difference inacid strength would be required in order to obtain comparable treatment.The sludge is separated after 9 to 12 hours standing and two additional4 pound dumps of 15 fuming acid are added followed by 6 to 8 hourssettling each time before withdrawing the lower Kill) pounds per gallonof charge or 0.5 pound per gallon per dump in three dumps. Where thespray oil is to have an unsulfonated residue of approximately 87% as ispreferred (when the sulfonates are washed out with alcohol the same oilwould have an unsulfonated residue of approximately 90%), somewhat moreor less acid may be required depending upon the particular stock beingtreated.

Sufficient caustic potash or caustic soda of 48 to 50 Baum strength isthen added to exactly neutralize the batch. The batch is blown with airduring the addition of caustic and for one hour after adding thecaustic. 'The batch is then air blown at 140 F. for one hour or untilthe water content is .1% or less. In general, 70 to 80 cc. of 48 Baumcaustic soda will be suflicient to neutralize each gallon of charge or.02 gallon of 40 Baum caustic soda per gallon of oil charged. Onehundred to 110 cc. of 48 Baum caustic potash will be required toneutralize each gallon of charge or 026 to .029 gallon of 48- Baumcaustic potash per gallon of oil charged.

The major part of the inorganic salts will separate on 24 hoursstanding. Where a bright emulsifiable oil is required, centrifuging maybe desirable.

Strong caustic or potash, as distinguished from the 20 Baum caustic sodaordinarily used in such a neutralization process, is utilized in orderto cut down on the amount of water added and thus prevent a separationof the sulfonates to the aqueous layer. This concentrated solution ofalkali also shortens the time required for air blowing in order toproduce a-product with a good color.

An'oil prepared by the above process using 481 Baum KOH as theneutralizing agent has the following characteristics:

Gravity (A. P. I.) 26.4 Flash point; 320 F. Fire point 365 F. Viscosityat 100 F 98 Unsulfonated residue 87 Percent sulfonates 2.5

Percent water Trace This oil readily emulsified with water in theproportions of 2 parts of oil to 98 parts of water and remainedemulsified for two hours.

The color of the finished product was superior to that obtained whensulfonates are added to the oil, due to the fact that sulfonates asordinarily produced are heated to 210- to 240 F. to remove water and theheating darkens the sulfonates considerably. The process of thisinvention avoids the deterioration resulting from heat.

give a partially refined oil having an unsulfonatable residue of atleast approximately treating said refined oil with sulfuric acid to formreactionproducts therein having the characteristics of sulfonic acids,neutralizing said reaction products with an alkali, and maintaining insolution in the oil a substantial portion of said neutralized reactionproducts as an emulsifying agent for the completed oil, said retainedportion comprising from approximately 0.4% to approximately 10% byweight of said oil.

2. A process of producing a soluble phytonomic insecticidal oilcomprising treating a mineral oil with sulfuric acid to form a solutionin the oil of reaction products having characteristics of sulfonicacids, separating sludge formed by said acid treatment from said oilsolution, neutralizing said oil solution of reaction products with analkali, and maintaining in solution in the oil without removal therefroma substantial portion of said neutralized reaction products as anemulsifying agent for the completed insecticidal oil, said retainedportion of neutralized reaction products comprising from approximately0.4% to approximately 10.0% by weight of said oil.

3. A process of producing an insecticidal oil comprising treating arefined petroleum oil having an average molecular weight in the range of200 to 400 and an unsulfonatable residue of 80% or more, withconcentrated sulfuric acid to form an oil solution of reaction productshaving characteristics of sulfonic acids, neutralizing said reactionproducts with an aqueous solution of an alkali, and maintaining insolution in the oil a portion of said neutralized reaction products asan emulsifying agent for the completed soluble oil, said retainedportion comprising from approximately 0.4% to approximately 10% byweight of said cbmpleted oil.

4. A process of producing an insecticidal oil comprising treating aphytonomic petroleum oil having a molecular weight in the range of 200to 400, a viscosity offrom 50 to 100 seconds Saybolt at 100 F. and anunsulfonatable residue of at least approximately 80%, with concentratedsulfuric acid to form an oil solution of reaction products comprisingsulfonic acids, neutralizing said reaction products with an alkali, andmaintaining in solution in the oil a portion of said neutralizedreaction products as an emulsifying agent for-the completed insecticidaloil, said retained portion comprising from approximately 2 toapproximately 4% by weight of said insecticidal oil.

5. A process of producing a soluble oil comprising treating a mineraloil having an unsulfonatable residue of from approximately 80 to withsulfuric acid to form an oil solution of reaction products havingcharacteristics of sulfonic acids, 'se'paratingsludge formed by saidacid treatment'from said oil solution, neutralizing said reactionproducts with an alkali, and maintaining in solution in the oil from 0.4to 10% by weight of said neutralized reaction products as an emulsifyingagent for the completed soluble oil.

- H. HAMPTON.

-NORMAN N. GAY.

